In the disclosure of the present invention reference is mostly made to the treatment of diabetes by infusion of insulin, however, this is only an exemplary use of the present invention.
Portable drug delivery devices for delivering a drug to a patient are well known and generally comprise a reservoir adapted to contain a liquid drug, a pump assembly for expelling a drug out of the reservoir and through the skin of the subject via a transcutaneous access device such as a soft cannula or a needle. Such devices are often termed infusion pumps.
Basically, infusion pumps can be divided into two classes. The first class comprises durable infusion pumps which are relatively expensive pumps intended for 3-4 years use, for which reason the initial cost for such a pump often is a barrier to this type of therapy. Although more complex than traditional syringes and pens, the pump offer the advantages of continuous infusion of insulin, precision in dosing and optionally programmable delivery profiles and user actuated bolus infusions in connections with meals. Such pumps are normally carried in a belt or pocket close to the body.
Addressing the above cost issue, several attempts have been made to provide a second class of drug infusion devices that are low in cost yet convenient to use. Some of these devices are intended to be partially or entirely disposable and may provide many of the advantages associated with an infusion pump without the attendant costs. For example, U.S. Pat. No. 6,589,229 discloses a skin-mountable drug infusion device which may have a two-part construction in which more expensive electronic components are housed in a reusable portion and the fluid delivery components are housed in a separable disposable portion (i.e. intended for single use only). U.S. Pat. No. 6,656,159 discloses a skin-mountable drug infusion device which is fully disposable.
The traditional durable pump may be worn in a belt at the waist of the user, this allowing the user to operate the pump by directly accessing the user interface on the pump, e.g. in order to change infusion rate or to program a bolus infusion. However, the pump may also be worn hidden under clothing making this operation more difficult.
Correspondingly, it has been proposed to provide an infusion pump of the durable type with a wireless remote controller allowing the user to access some or all of the functionality of the pump, see for example U.S. Pat. No. 6,551,276, US 2003/0065308, US 2005/0022274, US 2005/0171513, US 2006/0017576 and US 2006/0020300, which are hereby incorporated by reference. The pump and controller may be adapted to communicate with further devices, e.g. US 2005/0171513 discloses a remote controller which may also communicate with external devices such as a glucose monitor, cell phone, PDA or computer using its RF transmitter/receiver, US 2006/0017576 discloses an implantable pump which has two different communication means allowing it to communicate with two different external control devices, and US 2006/0020300 discloses an implantable device to which an external antenna can be coupled to increase communication distance before implantation.
For a skin-mountable device, typically comprising an adhesive allowing the device to be attached directly to the skin of the user, a remote controller would appear even more desirable. Correspondingly, U.S. Pat. No. 6,589,229 and U.S. Pat. No. 6,740,059, which are hereby incorporated by reference, disclose semi-disposable and fully disposable infusion devices (which may be termed a local device or unit) which are intended to be operated primarily or entirely by a wireless remote controller (which may be termed a remote device or unit). As the delivery device thus does not have to be provided with a user interface such as a display and keyboard, the semi-disposable or disposable infusion can be provided more cost-effectively.
In order to provide safe operation of a given delivery device it is of utmost importance that control commands sent from a given remote control unit only control actuation of the specific delivery device it is intended to control, and not some other delivery device in the proximity of the user. Further, as the delivery device may be adapted to transmit information back to the remote controller, it is also essential that such information is only received by the corresponding control unit. This issue is applicable to both durable systems and systems comprising disposable units. To provide the desired security the two devices intended to work together will normally be “paired” by exchange of information between the two devices, this allowing the information sent between the two devices to be specifically coded and thus only accepted by the correspondingly coded device. As appears, when a specific remote controller is to be paired with a specific delivery device it is of utmost importance that it is in fact the two devices which are intended to be paired that are actually paired—and not that the remote controller is accidentally being paired with a neighboring delivery. During a pairing process other information may also be transmitted between the two devices, e.g. the controller may be provided with information as to the type of delivery device in case different types of delivery devices are intended to be used with a given remote controller.
However, even if a remote controller has been correctly paired with a given delivery device, it may still be possible to control the delivery device in an undesired way. For example, if a remote controller comes into the hands of a third person, it may be possible for that person to control the delivery device, typically without the knowledge of the user of the delivery device. For example, a child may find the remote controller and start to play with it, this resulting in the inadvertently transmission of infusion commands to the delivery device, e.g. the infusion of a bolus of insulin.
Having regard to the above, it is the object of the present invention to provide devices and methods allowing secure pairing of two electronically controlled devices adapted to communicate with each other, either one-way or two-way. It is a further object of the invention to provide such devices and methods which provide safety of use and which to a high degree protect against the inadvertent transmission of data, e.g. commands, between two electronically controlled devices.